How Ukraine and Pro-Russian Separatists Traded Unconvicted Prisoners

Back in December 2014, Serhiy Shulakov was busy fixing cars in his company's auto-service yard in the eastern Ukrainian town of Popasna when he saw a hand reaching over the fence.

The hand that was trying to unlock the gate belonged to a member of the Ukrainian Security Service, the SBU.

"I open up, and it's SBU operatives," Shulakov recalled. "The usual stuff - first thing, they take me down hard, I had to lie face-down in the snow for a bit. But nothing too bad. They search the service yard, find nothing. Then they go to my home and find ammunition, which I have a permit for. At the time, I was certain it would all be resolved and all would be well."

But the SBU then accused the 42-year-old businessman from Popasna, which lies on the frontline between government-controlled and separatist-held areas in Ukraine's Luhansk region, of aiding the Russian backed separatists by helping them train their fire on their targets during an artillery strike on his hometown.

The accusations against Shulakov were based on a phone conversation he had with an acquaintance who had joined the separatist militia of the so-called Luhansk People's Republic.

"Their conversation was roughly as follows: 'Serhiy, we're shelling Popasna today, are you willing to spot [guide artillery fire] for us?' Shulakov's reply was yes, that he'd do it. This conversation was recorded," explained Shulakov's lawyer Artur Simeyko.

"Then another conversation was recorded with an 'unidentified man' - Shulakov calls and says good afternoon, I need to see you, immediately," Simeyko added.

Shulakov spent almost a month in a remand centre, unable to contact his relatives or a lawyer. Even though he hadn't been convicted of anything, the SBU then delivered him to the...